|Canon 24mm f/1.4L II lens|
The Canon 24mm f/1.4L II lens seemed like the perfect answer for my star photography. All the reviews I read said that it performed well, even wide open, with only moderate vignetting (which is important when you want to stitch several images together into a panorama). By being able to shoot at f/1.4, I could lower my ISO and greatly reduce the noise I had been getting in my starry night skies.
None of the reviews mentioned the problem of coma. To my horror, I noticed stars in my photographs that were shaped more like white doves in flight! Returning to the Canon dealer in distress, I was told the only solution was to stop down my new 24mm lens. (Note: Not all aspherical lens designs are created equal. This expensive Canon lens has two high-precision aspherical elements, and 2-UD elements, but exhibits much more coma than another prime lens costing about one-third the price!)
|Canon 24mm @ f/1.4: enlarged area near the edge shows stars with severe coma distortion (click image to enlarge).|
|Aspherical elements in Samyang Optics 24mm f/1.4|
|Aspherical lenses by Samyang Opics: 14mm f/2.8 - 24mm f/1.4 - 35mm f/1.4|
Recommendations and Reviews: Several of my night photography friends have purchased these lenses and recommend them. For example, Masahiro Miyasaka (Astrononomy Photographer of the Year 2012) uses the 14mm; Mike Berenson uses the 24mm; and David Kingham uses the 35mm for awesome panoramas. I have the 24mm and the 14mm.
|Grand Canyon with the Milky Way - taken with Rokinon 14mm f/2.8 ~ © Royce Bair (click to enlarge)|
|Grand Canyon - Nankoweep area - taken with Rokinon 24mm f/1.4 ~ © Royce Bair (click to enlarge)|
The Samyang / Rokinon 35mm is probably the least purchased starscape lens because of its narrower 63º angle of view. However, because it has a less distorted view (closer to that of a normal lens) than most wider angle lenses, it is preferred by many photographers for panoramas, where several vertical images are stitched together (like this one by David Kingham). Here's a Digital-Picture review on the Samyang 35mm.
NOTE: All of these lenses are designed for full-frame camera sensors (i.e. a Nikon FX). They can be used on a Nikon DX camera or a Canon camera with an APS-C size sensor, but the angles of view are less. The angle of view with the 14mm becomes 94º using the Nikon APS-C sensor, and 90º using the Canon APS-C sensor. The angle of view with the 24mm becomes 62º using the Nikon APS-C sensor, and 58º using the Canon APS-C sensor. The angle of view with the 35mm becomes 43º using the Nikon APS-C sensor, and 41º using the Canon APS-C sensor.
Pricing and ordering: (the links are to B&H, which often has lower than list pricing)
Rokinon 14mm f/2.8 Nikon mount - Canon mount - Sony mount ~ List: $399.00
Rokinon 24mm f/1.4 Nikon mount - Canon mount - Sony mount ~ List: $599.00
Rokinon 35mm f/1.4 Nikon mount - Canon mount - Sony mount ~ List: $499.00
(Disclosure: using these links give me a 2% referral commission, but add nothing to your cost. Thanks for your support!)
More Low Coma Lens Recommendation
Here is my first article on Overcoming Coma.